Forty millimeter caliber exercise bullet

ABSTRACT

A forty millimeter caliber exercise bullet has improved for properly exploding on a target, and securely maintaining the unloaded status during ordinary time. The improved exercise bullet comprising that; a skirt ( 200 ), a striking pin ( 10 ), a safety device assembly ( 300 ) consisting a detent cover ( 310 ) with a central mounting groove ( 311 ) and a pair of mounting grooves ( 312 ), a detent ( 320 ) for retaining the striking pin ( 10 ) by engaging or disengaging into the circumferential groove ( 11 ) by springs ( 323 ), a detonator cap ( 330 ) forming a hollow pocket ( 331 ) to insert a detonator trigger ( 20 ), a washer ( 30 ), and a press-spring ( 332 ) for pressing a guiding cap ( 340 ), an explosion pipe ( 400 ), a smoke shell ( 500 ), and an ogive ( 600 ). When the bullet is fired, the rotation of bullet generates centrifugal force to slide the retainer outward for disengaging the circumferential groove, then the striking pin moves upward to impact the detonator trigger when it hit on the target.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exercise bullet for training a grenade launcher. More particularly, a forty millimeter caliber exercise bullet has improved to be more reliable and safer, when it handles unloaded status or loaded status. When a projectile is flown after firing, the explosion properly takes place at an impact point during the exercise for utilizing the grenade launcher.

2. Related Prior Art

A conventional forty millimeter caliber exercise bullet is configured when a firing pin of the grenade launcher strikes a detonator of a bullet; a propellant in the bullet shell is primarily ignited for launching a projectile. The firing pin will strike a detonator trigger to ignite the smoke screen generating agent when the projectile hit on the ground. Due to instant combustion of the propellant, the pressure rapidly increased to expel the projectile. Because of the impact, a smoke screen is generated; thereby the trainer easily recognizes that the bullet hits on the target during the shooting exercise.

However, the conventional exercise bullet has the explosion problem that the detonator trigger or a firing pin often fails to ignite or discharge the projectile due to the occurrence of the malfunctions. Because the mal-operation of the detonator trigger or the firing pin, the smoke screen generation agent is not properly ignited. Thus, it causes the difficulty to perform the training. Specifically, a head part of the projectile, i.e., an ogive (wind shell) is not ruptured at the impact point. Even though the ogive is ruptured, the smoke screen generating agent does not ignite to explode, because the transmitted force is not strong enough to reach a fuse. Because the firing pin does not properly operate, the proper force fails to transmit to the detonator trigger. Thus, the detonator trigger will not strike to ignite the smoke screen generating agent for launching the projectile. Thus, the conventional exercise bullet has often incurred a trouble and it cause to fail the training of the grenade launcher.

Therefore, a research is required for developing the reliable and safe device for smooth operation of the grenade launcher. The reliable exercise bullet will not ignite the fuse when it is accidently dropped and hit on the ground or an unexpected accident occurred due to miss-handling at the unfamiliar circumferences.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems. The object of the present invention is to provide an improved forty millimeter caliber exercise bullet, which is more reliable and secures safety, when it handles unloaded status for storing or loaded status under training environment. When a projectile is flown after firing during an exercise of the grenade launcher, the bullet maintains a loaded status to avoid failure of the explosion at an impact point.

According to the present invention, the objects is to accomplish the provision of the improved forty millimeter caliber exercise bullet, comprising that; a cartridge assembly (100) forming cylindrical shape with hollow inside, so that it contains a percussion primer (110) and primer housing (120) at central lower portion; a skirt (200) forming cylindrical shape with thread on inside surface of lower central portion, outer surface having rounded bottom for fixedly inserting to the cartridge assembly (100); a striking pin (10) forming a circumferential groove (11) on out surface of lower portion; a safety device assembly (300) consisting a detent cover (310) having disk shape with a central mounting groove (311) for seating the striking pin (10) and a pair of mounting grooves (312) connected to the mounting seat (311) in radial direction; a detent (320) for retaining the striking pin (10) by engaging or disengaging into the circumferential groove (11) by springs (323), the detent (320) having a retainer (321) at one side and a mounting stub (322) at other side; a detonator cap (330) forming a hollow pocket (331) at its central upper portion to insert a detonator trigger (20), a washer (30), sequentially from the top and install a press-spring (332) for pressing a guiding cap (340) encompassed the striking pin (10), and the detonator cap (330) is bolted to the detent cover (310), so that the retainer (321) slides outward by centrifugal force to disengage the circumferential groove (11), then the striking pin (10) moves upward to impact the detonator trigger (20); an explosion pipe (400) filled with an explosive agent, and threaded the lower central portion of the skirt (200) for fixedly connecting to the detonator cap (330) and the detent cover (310); a smoke shell (500) filled with a smoke screen generating agent and the lower portion of the smoke shell (500) is inserted between the upper inside of the skirt (200) and the outer side of the explosion pipe (400); and an ogive (600) for surrounding the smoke shell (500) and the lower portion of the ogive (600) fixedly inserting to the outer upper portion of the skirt (200).

The mounting grooves (312) are arranged either one of 180° angle, or 120° angle in the radial directions.

The detent (320) forms the retainer (321) at one side and the mounting stub (322) at other side for retaining the striking pin (10) by engaging or disengaging into the circumferential groove (11) of striking pin (10). The retainer (321) has either one of rectangular shape or cylindrical shape.

The detonator cap (330) forms the hollow pocket (331) for mounting the striker pin (10) and a through hole for passing a needle of the striking pin (10) when the retainer (321) moves outward by the centrifugal force to disengage the circumferential groove (11), then the striking pin (10) moves upward by the press-spring (332) to impact the detonator trigger (20).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an exploded forty millimeter caliber exercise bullet according to the present invention.

FIG. 2 is a cross-sectional view illustrating the forty millimeter caliber exercise bullet according to the present invention.

FIG. 3 is a cross-sectional view illustrating unloaded status and loaded status of the forty millimeter caliber exercise bullet according to the safety device assembly of the present invention.

FIGS. 4A & 4B are illustrating the safety device assemblies of the forty millimeter caliber exercise bullets according to the embodiments of the present invention.

FIG. 5 is illustrating a safety device assembly of the forty millimeter caliber exercise bullet according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an improved forty millimeter caliber exercise bullet of the present invention will describe in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an exploded forty millimeter caliber exercise bullet according to the present invention, and FIG. 2 is a cross-sectional view illustrating the forty millimeter caliber exercise bullet according to the present invention.

The forty millimeter caliber exercise bullet of the present invention basically includes a cartridge assembly 100, which contains a percussion primer 110 and a primer housing 120, a skirt 200 being inserted into the cartridge assembly 100, a safety device assembly 300 for controlling a striking pin 10 to strike a detonator trigger 20, an explosion pipe 400 disposed in front of the safety device assembly 300, a smoke shell 500 surrounding the explosion pipe 400, and an ogive 600 surrounding the smoke shell 500.

In the cartridge assembly 100, when a firing pin of a grenade launcher strikes the percussion primer 110, a propellant in the primer housing 120 is ignited and the exercise bullet is ejected from the grenade launcher due to the instant combusting pressure. For this purpose, the cartridge assembly 100 formed cylindrical shape with hollow inside contains the percussion primer 110 and the primer housing 120 in the center lower portion thereof.

The skirt 200 having cylindrical shape has formed a rounded bottom on the outer lower portion for inserting into the cartridge assembly 100 and threaded on central inner side of the skirt 200. Thus, the skirt 200 contains the safety device assembly 300 and connects to the explosion pipe 400, the smoke shell 500 and the ogive 600. When the exercise bullet hits on the ground, the skirt 200 protects and activate the safety device assembly 300.

FIG. 3 is a cross-sectional view illustrating unloaded status and loaded status of the forty millimeter caliber exercise bullet according to the safety device assembly of the present invention.

When the exercise bullet is fired, the shell will be rotated by means of the spiral grooves formed inside of the grenade launcher. Then, the exercise bullet in loaded status will activate the safety device assembly 300. When the exercise bullets are stored or transported, it will be in unloaded status. For this purpose, the safety device assembly 200 consists a detent cover 310 having disk shape, a central mounting groove 311 at the center, so that a bottom of the striking pin 10 with a circumferential groove 11 on its outside lower portion is seated into the central mounting groove 311 and a pair of mounting grooves 312 connected in radial direction to the central mounting groove 311. The detents 320 are disposed in the mounting grooves 312, so that retainers 321 at one side of detents 320 are sliding to engage or disengage the circumferential groove 11 by springs 323 mounted on the mounting stubs 322 at the other side of the detent 320, and a detonator cap 330 having a hollow pocket at the central portion thereof. The hollow pocket 331 is formed on the upper portion for sequentially inserting the detonating trigger 20, a washer 30 from the top. A press-spring 332 is inserted into the hollow pocket 331 for pressing a guiding cap 340, which is encompassed the striking pin 10. Then, the detonator cap 330 has bolted to the detent cover 310.

Through the above-described structure of the safety device assembly 300, the exercise bullet is fired. As far as the retainers 321 of the detents 320 engage to the circumferential groove 11 of the striking pin 10 by the spring 323, the exercise bullet will not exploded. Even though, an impact is applied to a head of the exercise bullet, i.e., impact on the ogive 600, the striking pin 10 will not strike the detonator trigger 20, if the striking pin 10 is locked by the retainers 321. However, the centrifugal force generated by rotation of the shell after firing the exercise bullet, for example, the rotation is approximately 3,600 RPM will be applied to the detents 320 for sliding outward. The retainers 321 are shifting outward to disengage the groove 11 of the striking pin 10, and the striking pin 10 impacts the detonator trigger 20 when the ogive 600 impacts on the ground, then the exercise bullet explodes.

FIGS. 4A & 4B and FIG. 5 are illustrating the safety device assembly of the forty millimeter caliber exercise bullet according to the present invention.

Here, a pair of the mounting grooves 312 is aligned in radial directions, so that the detents 320 are arranged to be 180° angle in two directions for retaining the striking pin 10. Alternatively, it is possible to arrange the plural mounting grooves 312 to be 120° angle in three directions, so that the striking pin 10 can be retained more firmly in three directions for the loaded status when the projectile is rotating or the unloaded status in the stationary situations.

Further, a detent block 324 is integrally formed with the retainer 321 and the mounting stub 322 of detent 320. The retainers 321 formed rectangular shape are inserted in the mounting grooves 312 for smooth sliding. Alternatively, the detent block 324 with the retainers 321 may form cylindrical shape to reduce a frictional resistance. The detents 320 are sliding in the mounting grooves 312 for engaging or disengaging into the circumferential groove 11 of the striking pin 10 to convert the safety device assembly 300 from unloaded status to loaded status. The detent 320 having cylindrical shape is more reliable in operation as compared to the detent 320 having rectangular shape.

In addition, a guiding cap 340 is further installed inside the detonator cap 330 after inserting a press-spring 332 from the bottom. The guiding cap 340 is encompassed the striking pin 10 and have a through hole to pass a needle of the striking pin 10. The guiding cap 340 will move downward by the press-spring 332 to overlap the circumferential groove 11 of the striker pin 10 when the retainers 321 of the detents 320 are disengaged from the circumferential groove 11 of the striker pin 10. Therefore, the guiding cap 340 will prevent the retainer 321 re-engaging into the circumferential groove 11, which cause the failure of exploding the exercise bullet. Due to the centrifugal force and impact force will explode the exercise bullet when bullet hits on the target.

The explosion pipe 400 is filled with the explosive agent, which is made of an environmentally friendly degradable resin, such as poly lactic acid (PLA). The lower portion of the explosion pipe 400 is thread-connected to the central portion of the skirt 200. The explosion pipe 400 is fixedly mounted in front of the detonator cap 330 and the detent cover 310 for inducing ignition of the explosive agent by triggering the detonator trigger 20.

The smoke shell 500 is filled with a smoke screen generating agent. The lower portion of the smoke shell 500 is inserted into a clearance between the inside upper portion of the skirt 200 and the outer side of the explosion pipe 400. The smoke shell 500 explodes together with the explosion pipe 400, thereby combusting the smoke screen generating agent for generating a smoke screen. Although the inside of the smoke shell 500 may be filled with the smoke screen generating agent alone, or the inside of the smoke shell 500 may be filled with a combination of a smoke screen generating agent, an environmentally friendly smoke screen pigment and a color fixing agent mixed with soil. Therefore, it will generate the smoke screen to easily distinguish and scatter the soil when of the smoke shell 500 exploded.

The ogive 600 is made of an environmentally friendly degradable resin, such as poly lactic acid (PLA), which is the same material of the explosion pipe 400. The lower portion of the ogive 600 is fixedly mounted on the upper outside of the skirt 200 to encompass the smoke shell 500 and the ogive 600 is ruptured when the exercise bullet is fired and collides on the impact point.

Hereinafter, an operation will be described for the forty millimeter caliber exercise bullet having the structure as describe above.

When an exercise bullet is loaded and fired through a grenade launcher, the percussion primer 110 is hit, and the propellant in the primer housing 120 is ignited. Then, the skirt 200, the safety device assembly 300, and the smoke shell 500 and the ogive 600 as a whole integral projectile is instantly launched to separate from the cartridge assembly 100 flown toward an impact point. As soon as firing, the exercise bullet is rotating by the spiral grooves formed on the grenade launcher. The detents 320 of the safety device assembly 300 are sliding outward by the centrifugal force. Then, the striking pin 10 will be free to move. When the exercise bullet collides on the impact point, the striking pin 10 moves forward to impact the detonator trigger 20. Consequently, the explosive agent in the explosion pipe 400 and the smoke screen generating agent (including the color fixing agent and the smoke screen pigment) in the smoke shell 500 are ignited, simultaneously generating the smoke screen with a noise of explosion.

As apparent from the above description, the forty millimeter caliber exercise bullet of the present invention allowing the detents sliding outward by centrifugal force due to the rotation, then the striking pin properly hits the detonator due to impact at an impact point only when the exercise bullet is fired while being rotated by the spiral grooves of the grenade launcher, thereby greatly reducing the dud rate. Further, the forty millimeter caliber exercise bullet of the present invention maintains the detent to retain the striking pin in stationary state during the storage or transportation situation.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A forty millimeter caliber exercise bullet, comprising: a cartridge assembly (100) forming cylindrical shape with hollow inside, so that it contains a percussion primer (110) and primer housing (120) at central lower portion, a skirt (200) forming cylindrical shape with thread on inner surface of lower central portion, outer surface having rounded bottom for fixedly inserting to the cartridge assembly (100), a striking pin (10) forming a circumferential groove (11) on outer surface of lower portion, a safety device assembly (300) consisting a detent cover (310) having disk shape with a central mounting groove (311) for seating the striking pin (10) and a pair of mounting grooves (312) connected to the mounting seat (311) in radial direction, a detent (320) for retaining the striking pin (10) by engaging or disengaging into the circumferential groove (11) by springs (323), said detent (320) having a retainer (321) at one side and a mounting rod (322) at other side, a detonator cap (330) forming a hollow pocket (331) at its central upper portion to insert a detonator trigger (20), a washer (30), sequentially from the top and install a press-spring (332) for pressing a guiding cap (340) encompassed the striking pin (10), and the detonator cap (330) is bolted to the detent cover (310), so that the retainer (321) shifts outward by the centrifugal force to disengage from the circumferential groove (11), then the striking pin (10) free to move upward to impact the detonator trigger (20), an explosion pipe (400) filled with an explosive agent, and threaded the lower central portion of the skirt (200) for fixedly connecting to the detonator cap (330) and the detent cover (310), a smoke shell (500) filled with a smoke screen generating agent and the lower portion of the smoke shell (500) is inserted between the upper inside of the skirt (200) and the outer side of the explosion pipe (400), and an ogive (600) for surrounding the smoke shell (500) and the lower portion of the ogive (600) fixedly inserting to the outer upper portion of the skirt (200).
 2. The forty millimeter caliber exercise bullet according to claim 1, wherein the mounting grooves (312) are arranged either one of 180° angle in the radial directions, or 120° angle in the three directions.
 3. The forty millimeter caliber exercise bullet according to claim 1, wherein said detent (320) is integrally formed with the retainer (321) at one side and the mounting rod (322) at other side as a piece for retaining the striking pin (10) by engaging or disengaging into the circumferential groove (11), the retainer (321) having either one of rectangular shape or cylindrical shape.
 4. The forty millimeter caliber exercise bullet according to claim 1, wherein the detonator cap (330) forms the hollow pocket (331) for sequentially inserting the press-spring (332), the guiding cap (340) and the striker pin (10) from the bottom.
 5. The forty millimeter caliber exercise bullet according to claim 4, wherein the smoke shell (500) fills the smoke screen generating agent, which is an environmentally friendly smoke screen pigment and a color fixing agent mixed with soil. 